Mesenchymal stromal cell-derived extracellular vesicles therapy openings new translational challenges in immunomodulating acute liver inflammation.

Inflammation plays a critical role in conditions such as acute liver failure, acute-on-chronic liver failure, and ischemia-reperfusion-induced liver injury. Various pathogenic pathways contribute to liver inflammation, involving inflammatory polarization of macrophages and Küpffer cells, neutrophil infiltration, dysregulation of T cell subsets, oxidative stress, and activation of hepatic stellate cells. While mesenchymal stromal cells (MSCs) have demonstrated beneficial properties, their clinical translation is limited by their cellular nature. However, MSC-derived extracellular vesicles (MSC-EVs) have emerged as a promising cell-free therapeutic approach for immunomodulation. MSC-EVs naturally mirror their parental cell properties, overcoming the limitations associated with the use of MSCs. In vitro and in vivo preclinical studies have demonstrated that MSC-EVs replicate the beneficial effects of MSCs in liver injury. This includes the reduction of cell death and oxidative stress, improvement of hepatocyte function, induction of immunomodulatory effects, and mitigation of cytokine storm. Nevertheless, MSC-EVs face challenges regarding the necessity of defining consistent isolation methods, optimizing MSCs culture conditions, and establishing quality control measures for EV characterization and functional assessment. By establishing standardized protocols, guidelines, and affordable cost mass production, clinicians and researchers will have a solid foundation to conduct further studies, validate the therapeutic efficacy of MSC-EVs, and ultimately pave the way for their clinical implementation in acute liver injury.

Lung Ultrasound Score on Postoperative Day 1 Is Predictive of the Occurrence of Pulmonary Complications after Major Abdominal Surgery: A Multicenter Prospective Observational Study.

BACKGROUND: Postoperative pulmonary complications after major abdominal surgery are frequent and carry high morbidity and mortality. Early identification of patients at risk of pulmonary complications by lung ultrasound may allow the implementation of preemptive strategies. The authors hypothesized that lung ultrasound score would be associated with pulmonary postoperative complications. The main objective of the study was to evaluate the performance of lung ultrasound score on postoperative day 1 in predicting pulmonary complications after major abdominal surgery. Secondary objectives included the evaluation of other related measures for their potential prediction accuracy. METHODS: A total of 149 patients scheduled for major abdominal surgery were enrolled in a bicenter observational study. Lung ultrasound score was performed before the surgery and on days 1, 4, and 7 after surgery. Pulmonary complications occurring before postoperative day 10 were recorded. RESULTS: Lung ultrasound score on postoperative day 1 was higher in patients developing pulmonary complications before day 10 (median, 13; interquartile range, 8.25 to 18; vs. median, 10; interquartile range, 6.5 to 12; Mann-Whitney P = 0.002). The area under the curve for predicting postoperative pulmonary complications before day 10 was 0.65 (95% CI, 0.55 to 0.75; P = 0.003). Lung ultrasound score greater than 12 had a sensitivity of 0.54 (95% CI, 0.40 to 0.67), specificity of 0.77 (95% CI, 0.67 to 0.85), and negative predictive value of 0.74 (95% CI, 0.65 to 0.83). Lung ultrasound score greater than 17 had sensitivity of 0.33 (95% CI, 0.21 to 0.47), specificity of 0.95 (95% CI, 0.88 to 0.98), and positive predictive value of 0.78 (95% CI, 0.56 to 0.93). Anterolateral lung ultrasound score and composite scores using lung ultrasound score and other patient characteristics showed similar predictive accuracies. CONCLUSIONS: An elevated lung ultrasound score on postoperative day 1 is associated with the occurrence of pulmonary complications within the first 10 days after major abdominal surgery.

Understanding the nebulisation of antibiotics: the key role of lung microdialysis studies.

BACKGROUND: Nebulisation of antibiotics is a promising treatment for ventilator-associated pneumonia (VAP) caused by multidrug-resistant organisms. Ensuring effective antibiotic concentrations at the site of infection in the interstitial space fluid is crucial for clinical outcomes. Current assessment methods, such as epithelial lining fluid and tissue homogenates, have limitations in providing longitudinal pharmacokinetic data. MAIN BODY: Lung microdialysis, an invasive research technique predominantly used in animals, involves inserting probes into lung parenchyma to measure antibiotic concentrations in interstitial space fluid. Lung microdialysis offers unique advantages, such as continuous sampling, regional assessment of antibiotic lung concentrations and avoidance of bronchial contamination. However, it also has inherent limitations including the cost of probes and assay development, the need for probe calibration and limited applicability to certain antibiotics. As a research tool in VAP, lung microdialysis necessitates specialist techniques and resource-intensive experimental designs involving large animals undergoing prolonged mechanical ventilation. However, its potential impact on advancing our understanding of nebulised antibiotics for VAP is substantial. The technique may enable the investigation of various factors influencing antibiotic lung pharmacokinetics, including drug types, delivery devices, ventilator settings, interfaces and disease conditions. Combining in vivo pharmacokinetics with in vitro pharmacodynamic simulations can become feasible, providing insights to inform nebulised antibiotic dose optimisation regimens. Specifically, it may aid in understanding and optimising the nebulisation of polymyxins, effective against multidrug-resistant Gram-negative bacteria. Furthermore, lung microdialysis holds promise in exploring novel nebulisation therapies, including repurposed antibiotic formulations, bacteriophages and immunomodulators. The technique's potential to monitor dynamic biochemical changes in pneumonia, such as cytokines, metabolites and inflammation/infection markers, opens avenues for developing theranostic tools tailored to critically ill patients with VAP. CONCLUSION: In summary, lung microdialysis can be a potential transformative tool, offering real-time insights into nebulised antibiotic pharmacokinetics. Its potential to inform optimal dosing regimen development based on precise target site concentrations and contribute to development of theranostic tools positions it as key player in advancing treatment strategies for VAP caused by multidrug-resistant organisms. The establishment of international research networks, exemplified by LUMINA (lung microdialysis applied to nebulised antibiotics), signifies a proactive step towards addressing complexities and promoting multicentre experimental studies in the future.

Impact of COVID-19 on posttraumatic stress disorder in ICU survivors: a prospective observational comparative cohort study.

BACKGROUND: Posttraumatic stress disorder (PTSD) after a stay in the intensive care unit (ICU) can affect one in five ICU survivors. At the beginning of the coronavirus disease 2019 (COVID-19) pandemic, admission to the ICU for COVID-19 was stressful due to the severity of this disease. This study assessed whether admission to the ICU for COVID-19 was associated with a higher prevalence of PTSD compared with other causes of ICU admission after adjustment for pre-ICU psychological factors. METHODS: This prospective observational comparative cohort study included 31 ICUs. Eligible patients were adult ICU survivors hospitalized during the first wave of COVID-19 pandemic in France, regardless of the reason for admission. The prevalence of presumptive diagnosis of PTSD at 6 months was assessed using the PTSD Checklist for DSM-5 (PCL-5). Sociodemographics, clinical data, history of childhood trauma (Childhood Trauma Questionnaire [CTQ]), and exposure to potentially traumatic events (Life Events Checklist for DSM-5 [LEC-5]) were assessed. RESULTS: Of the 778 ICU survivors included during the first wave of COVID-19 pandemic in France, 417 and 361 were assigned to the COVID-19 and non-COVID-19 cohorts, respectively. Fourteen (4.9%) and 11 (4.9%), respectively, presented with presumptive diagnosis of PTSD at 6 months (p = 0.976). After adjusting for age, sex, severity score at admission, use of invasive mechanical ventilation, ICU duration, CTQ and LEC-5, COVID-19 status was not associated with presumptive diagnosis of PTSD using the PCL-5. Only female sex was associated with presumptive diagnosis of PTSD. However, COVID-19 patients reported significantly more intrusion and avoidance symptoms than non-COVID patients (39% vs. 29%, p = 0.015 and 27% vs. 19%, p = 0.030), respectively. The median PCL-5 score was higher in the COVID-19 than non-COVID-19 cohort (9 [3, 20] vs. 4 [2, 16], p = 0.034). CONCLUSION: Admission to the ICU for COVID-19 was not associated with a higher prevalence of PTSD compared with admission for another cause during the first wave of the COVID-19 pandemic in France. However, intrusion and avoidance symptoms were more frequent in COVID-19 patients than in non-COVID-19 patients. TRIAL REGISTRATION: Clinicaltrials.gov Identifier NCT03991611, registered on June 19, 2019.

Association between combination antibiotic therapy as opposed as monotherapy and outcomes of ICU patients with Pseudomonas aeruginosa ventilator-associated pneumonia: an ancillary study of the iDIAPASON trial.

BACKGROUND: The optimal treatment duration and the nature of regimen of antibiotics (monotherapy or combination therapy) for Pseudomonas aeruginosa ventilator­associated pneumonia (PA-VAP) remain debated. The aim of this study was to evaluate whether a combination antibiotic therapy is superior to a monotherapy in patients with PA-VAP in terms of reduction in recurrence and death, based on the 186 patients included in the iDIAPASON trial, a multicenter, randomized controlled trial comparing 8 versus 15 days of antibiotic therapy for PA-VAP. METHODS: Patients with PA-VAP randomized in the iDIAPASON trial (short-duration-8 days vs. long-duration-15 days) and who received appropriate antibiotic therapy were eligible in the present study. The main objective is to compare mortality at day 90 according to the antibiotic therapy received by the patient: monotherapy versus combination therapy. The primary outcome was the mortality rate at day 90. The primary outcome was compared between groups using a Chi-square test. Time from appropriate antibiotic therapy to death in ICU or to censure at day 90 was represented using Kaplan-Meier survival curves and compared between groups using a Log-rank test. RESULTS: A total of 169 patients were included in the analysis. The median duration of appropriate antibiotic therapy was 14 days. At day 90, among 37 patients (21.9%) who died, 17 received monotherapy and 20 received a combination therapy (P = 0.180). Monotherapy and combination antibiotic therapy were similar for the recurrence rate of VAP, the number of extra pulmonary infections, or the acquisition of multidrug-resistant (MDR) bacteria during the ICU stay. Patients in combination therapy were exposed to mechanical ventilation for 28 ± 12 days, as compared with 23 ± 11 days for those receiving monotherapy (P = 0.0243). Results remain similar after adjustment for randomization arm of iDIAPASON trial and SOFA score at ICU admission. CONCLUSIONS: Except longer durations of antibiotic therapy and mechanical ventilation, potentially related to increased difficulty in achieving clinical cure, the patients in the combination therapy group had similar outcomes to those in the monotherapy group. TRIAL REGISTRATION: NCT02634411 , Registered 15 December 2015.

Agreement between pulse oximetry and arterial oxygen saturation measurement in critical care patients during COVID-19: a cross-sectional study.

Some publications suggest that pulse oximetry measurement (SpO2) might overestimate arterial oxygen saturation (SaO2) measurement in COVID-19 patients. This study aims to evaluate the agreement between SpO2 and SaO2 among COVID-19 and non-COVID-19 patients. We conducted a multicenter, prospective study including consecutive intensive care patients from October 15, 2020, to March 4, 2021, and compared for each measurement the difference between SpO2 and SaO2, also called the systematic bias. The primary endpoint was the agreement between SpO2 and SaO2 measured with the Lin concordance coefficient and illustrated using the Bland and Altman method. Factors associated with systematic bias were then identified using a generalised estimating equation. The study included 105 patients, 66 COVID-19 positive and 39 COVID-19 negative, allowing for 1539 measurements. The median age was 66 [57; 72] years with median SOFA and SAPSII scores of, respectively, 4 [3; 6] and 37 [31; 47]. The median SpO2 and SaO2 among all measurements was respectively 97 [96-99] and 94 [92-96] with a systematic bias of 0.80 [- 0.6; 2.4]. This difference was, respectively, 0.80 [- 0.7; 2.5] and 0.90 [- 0.3; 2.0] among COVID-19 positive and negative patients. Overall agreement measured with the Lin correlation coefficient was 0.65 [0.63; 0.68] with 0.61 [0.57; 0.64] and 0.53 [0.45; 0.60] among the COVID-19 positive and negative groups, respectively. Factors independently associated with the variation of the SpO2-SaO2 difference were the PaO2/FiO2 ratio and need for mechanical ventilation. In our population, agreement between SpO2 and SaO2 is acceptable. During the COVID-19 pandemic, SaO2 remains an efficient monitoring tool to characterise the level of hypoxemia and follow therapeutic interventions. As is already known about general intensive care unit patients, the greater hypoxemia, the weaker the correlation between SpO2 and SaO2.

One-year patient outcomes based on lung morphology in acute respiratory distress syndrome: secondary analysis of LIVE trial.

BACKGROUND: Acute respiratory distress syndrome (ARDS) has different phenotypes and distinct short-term outcomes. Patients with non-focal ARDS have a higher short-term mortality than focal ones. The aim of this study was to assess the impact of the morphological phenotypes of ARDS on long-term outcomes. METHODS: This was a secondary analysis of the LIVE study, a prospective, randomised control trial, assessing the usefulness of a personalised ventilator setting according to lung morphology in moderate-to-severe ARDS. ARDS was classified as focal (consolidations only in the infero-posterior part of the lungs) or non-focal. Outcomes were assessed using mortality and functional scores for quality of life at the 1-year follow-up. RESULTS: A total of 124 focal ARDS and 236 non-focal ARDS cases were included. The 1-year mortality was higher for non-focal ARDS than for focal ARDS (37% vs. 24%, p = 0.012). Non-focal ARDS (hazard ratio, 3.44; 95% confidence interval, 1.80-6.59; p < 0.001), age, McCabe score, haematological cancers, SAPS II, and renal replacement therapy were independently associated with 1-year mortality. This difference was driven by mortality during the first 90 days (28 vs. 16%, p = 0.010) but not between 90 days and 1 year (7 vs. 6%, p = 0.591), at which point only the McCabe score was independently associated with mortality. Morphological phenotypes had no impact on patient-reported outcomes. CONCLUSION: Lung morphologies reflect the acute phase of ARDS and its short-term impact but not long-term outcomes, which seem only influenced by comorbidities. TRIAL REGISTRATION: NCT02149589; May 29, 2014.

Treatment of COVID-19-associated ARDS with mesenchymal stromal cells: a multicenter randomized double-blind trial.

BACKGROUND: Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-induced acute respiratory distress syndrome (ARDS) causes high mortality. Umbilical cord-derived mesenchymal stromal cells (UC-MSCs) have potentially relevant immune-modulatory properties, whose place in ARDS treatment is not established. This phase 2b trial was undertaken to assess the efficacy of UC-MSCs in patients with SARS-CoV-2-induced ARDS. METHODS: This multicentre, double-blind, randomized, placebo-controlled trial (STROMA-CoV-2) recruited adults (≥ 18 years) with SARS-CoV-2-induced early (< 96 h) mild-to-severe ARDS in 10 French centres. Patients were randomly assigned to receive three intravenous infusions of 106 UC-MSCs/kg or placebo (0.9% NaCl) over 5 days after recruitment. For the modified intention-to-treat population, the primary endpoint was the partial pressure of oxygen to fractional inspired oxygen (PaO2/FiO2)-ratio change between baseline (day (D) 0) and D7. RESULTS: Among the 107 patients screened for eligibility from April 6, 2020, to October 29, 2020, 45 were enrolled, randomized and analyzed. PaO2/FiO2 changes between D0 and D7 did not differ significantly between the UC-MSCs and placebo groups (medians [IQR] 54.3 [- 15.5 to 93.3] vs 25.3 [- 33.3 to 104.6], respectively; ANCOVA estimated treatment effect 7.4, 95% CI - 44.7 to 59.7; P = 0.77). Six (28.6%) of the 21 UC-MSCs recipients and six of 24 (25%) placebo-group patients experienced serious adverse events, none of which were related to UC-MSCs treatment. CONCLUSIONS: D0-to-D7 PaO2/FiO2 changes for intravenous UC-MSCs-versus placebo-treated adults with SARS-CoV-2-induced ARDS did not differ significantly. Repeated UC-MSCs infusions were not associated with any serious adverse events during treatment or thereafter (until D28). Larger trials enrolling patients earlier during the course of their ARDS are needed to further assess UC-MSCs efficacy in this context. TRIAL REGISTRATION: NCT04333368. Registered 01 April 2020, https://clinicaltrials.gov/ct2/history/NCT04333368 .

Occurrence of Invasive Pulmonary Fungal Infections in Patients with Severe COVID-19 Admitted to the ICU.

Rationale: Whether severe coronavirus disease (COVID-19) is a significant risk factor for the development of invasive fungal superinfections is of great medical interest and remains, for now, an open question.Objectives: We aim to assess the occurrence of invasive fungal respiratory superinfections in patients with severe COVID-19.Methods: We conducted the study on patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related pneumonia admitted to five ICUs in France who had respiratory and serum sampling performed for specific screening of fungal complications.Measurements and Main Results: The study population included a total of 145 patients; the median age was 55 years old. Most of them were male (n = 104; 72%), were overweight (n = 99; 68%), and had hypertension (n = 83; 57%) and diabetes (n = 46; 32%). Few patients presented preexisting host risk factors for invasive fungal infection (n = 20; 14%). Their global severity was high; all patients were on invasive mechanical ventilation, and half (n = 73, 54%) were on extracorporeal membrane oxygenation support. Mycological analysis included 2,815 mycological tests (culture, galactomannan, ß-glucan, and PCR) performed on 475 respiratory samples and 532 sera. A probable/putative invasive pulmonary mold infection was diagnosed in 7 (4.8%) patients and linked to high mortality. Multivariate analysis indicates a significantly higher risk for solid organ transplant recipients (odds ratio, = 4.66; interquartile range, 1.98-7.34; P = 0.004). False-positive fungal test and clinically irrelevant colonization, which did not require the initiation of antifungal treatment, was observed in 25 patients (17.2%).Conclusions: In patients with no underlying immunosuppression, severe SARS-CoV-2-related pneumonia seems at low risk of invasive fungal secondary infection, especially aspergillosis.

Educational interventions to integrate surgical staff within medical units during the COVID-19 pandemic: EDUCOVID survey.

BACKGROUND: The SARS-CoV-2 (COVID-19) pandemic required a rapid surge of healthcare capacity to face a growing number of critically ill patients. For this reason, a support reserve of physicians, including surgeons, were required to be reassigned to offer support. OBJECTIVE: To realize a survey on the educational programs deployed (face-to-face or e-learning focusing on infective area, basic gestures, COVID clinical management and intensive care medicine), and their impact on behavior change (Kirkpatrick 3) of the target population of surgeons, measured on a five modalities Likert scale. DESIGN: Cross-sectional online e-survey (NCT04732858) within surgeons from the Assistance Publique - Hôpitaux de Paris network, metropolitan area of Paris, France. RESULTS: Cross-sectional e-Survey: among 382 surgeons invited, 37 (9.7%) participated. The effectiveness of the educational interventions on behavior changes was rated within the highest region of the Likert scale by 15% (n = 3) and 22% (n = 6) for 'e-learning' and 'face-to-face' delivery modes, respectively. CONCLUSIONS: Despite the low response rate, this survey suggests an overall low impact on behaviour change among responders affiliated to a surgical discipline.

Nebulized antibiotics for ventilator-associated pneumonia: methodological framework for future multicenter randomized controlled trials.

PURPOSE OF REVIEW: Although experimental evidence supports the use of nebulized antibiotics in ventilator-associated pneumonia (VAP), two recent multicenter randomized controlled trials (RCTs) have failed to demonstrate any benefit in VAP caused by Gram-negative bacteria (GNB). This review examines the methodological requirements concerning future RCTs. RECENT FINDINGS: High doses of nebulized antibiotics are required to reach the infected lung parenchyma. Breath-synchronized nebulizers do not allow delivery of high doses. Mesh nebulizers perform better than jet nebulizers. Epithelial lining fluid concentrations do not reflect interstitial lung concentrations in patients receiving nebulized antibiotics. Specific ventilator settings for optimizing lung deposition require sedation to avoid patient's asynchrony with the ventilator. SUMMARY: Future RCTs should compare a 3-5 day nebulization of amikacin or colistimethate sodium (CMS) to a 7-day intravenous administration of a new cephalosporine/ß-lactamase inhibitor. Inclusion criteria should be a VAP or ventilator-associated tracheobronchitis caused by documented extensive-drug or pandrug resistant GNB. If the GNB remains susceptible to aminoglycosides, nebulized amikacin should be administered at a dose of 40 mg/kg/day. If resistant to aminoglycosides, nebulized CMS should be administered at a dose of 15 millions international units (IU)/day. In VAP caused by pandrug-resistant GNB, 15 millions IU/day nebulized CMS (substitution therapy) should be compared with a 9 millions IU/day intravenous CMS.

Mesenchymal Stem Cell-Derived Extracellular Vesicles Decrease Lung Injury in Mice.

Human mesenchymal stem cell (MSC) extracellular vesicles (EV) can reduce the severity of bacterial pneumonia, but little is known about the mechanisms underlying their antimicrobial activity. In the current study, we found that bacterial clearance induced by MSC EV in Escherichia coli pneumonia in C57BL/6 mice was associated with high levels of leukotriene (LT) B4 in the injured alveolus. More importantly, the antimicrobial effect of MSC EV was abrogated by cotreatment with a LTB4 BLT1 antagonist. To determine the role of MSC EV on LT metabolism, we measured the effect of MSC EV on a known ATP-binding cassette transporter, multidrug resistance-associated protein 1 (MRP1), and found that MSC EV suppressed MRP1 mRNA, protein, and pump function in LPS-stimulated Raw264.7 cells in vitro. The synthesis of LTB4 and LTC4 from LTA4 are competitive, and MRP1 is the efflux pump for LTC4 Inhibition of MRP1 will increase LTB4 production. In addition, administration of a nonspecific MRP1 inhibitor (MK-571) reduced LTC4 and subsequently increased LTB4 levels in C57BL/6 mice with acute lung injury, increasing overall antimicrobial activity. We previously found that the biological effects of MSC EV were through the transfer of its content, such as mRNA, microRNA, and proteins, to target cells. In the current study, miR-145 knockdown abolished the effect of MSC EV on the inhibition of MRP1 in vitro and the antimicrobial effect in vivo. In summary, MSC EV suppressed MRP1 activity through transfer of miR-145, thereby resulting in enhanced LTB4 production and antimicrobial activity through LTB4/BLT1 signaling.

Definition and Prospective Assessment of Functional Recovery After Liver Transplantation: A New Objective Consensus-Based Metric for Safe Discharge.

Standardized discharge criteria are critical to reduce premature discharge and avoid unnecessary hospital stays. No such criteria exist for patients undergoing liver transplantation (LT). To achieve a consensus-based checklist of criteria for safe patient discharge after LT, this mixed-method study included the following: a systematic literature review and expert discussion to draft a first checklist of post-LT discharge criteria, defining patient recovery and indications for hospital discharge (functional recovery); an exploratory online electronic Delphi (e-Delphi) study; a single-center pilot study to test checklist feasibility; and a final e-Delphi study with an extended interdisciplinary expert panel to validate the final checklist. The first round provided a 10-point discharge checklist with 5 patient-centered items derived from discharge criteria after liver surgery and 5 graft-centered items derived from expert discussion. The restricted panel (9 experts) e-Delphi provided 100% consensus after the second round, with slight modifications to the criteria. During the pilot study, 19 of 45 (42.2%) patients included fulfilled the complete checklist (100% of 10 items) after median (IQR) 16 (8-21) days (functional recovery) and a length of stay of 20 (9-24) days. The item with the lowest completion rate was minimum serum tacrolimus level in the target on 2 consecutive blood samples (n = 21; 47%), achieved at 13 (9-15) days. The extended panel (66 experts) e-Delphi provided 95%-98% consensus after the third round, with slight modifications of the criteria. This study provided substantial consensus on discharge criteria after LT. We anticipate that these criteria will be useful in clinical practice to guide patient discharge and increase the comparability of results between future studies.

Nebulization of Vancomycin Provides Higher Lung Tissue Concentrations than Intravenous Administration in Ventilated Female Piglets with Healthy Lungs.

BACKGROUND: Intravenous vancomycin is used to treat ventilator-associated pneumonia caused by methicillin-resistant Staphylococcus aureus, but achieves high rates of failure. Vancomycin nebulization may be efficient to provide high vancomycin lung tissue concentrations. The aim of this study was to compare lung tissue and serum concentrations of vancomycin administered intravenously and by aerosol in mechanically ventilated and anesthetized healthy piglets. METHODS: Twelve female piglets received a single intravenous dose of vancomycin (15 mg/kg) and were killed 1 (n = 6) or 12 h (n = 6) after the end of administration. Twelve piglets received a single nebulized dose of vancomycin (37.5 mg/kg) and were killed 1 (n = 6) or 12 h (n = 6) after the end of the aerosol administration. In each group, vancomycin lung tissue concentrations were assessed on postmortem lung specimens using high-performance liquid chromatography. Blood samples were collected for serum vancomycin concentration measurement 30 min and 1, 2, 4, 6, 8, and 12 h after the end of vancomycin administration. Pharmacokinetics was analyzed by nonlinear mixed effect modeling. RESULTS: One hour after vancomycin administration, lung tissue concentrations in the aerosol group were 13 times the concentrations in the intravenous group (median and interquartile range: 161 [71, 301] µg/g versus 12 [4, 42] µg/g; P < 0.0001). Twelve hours after vancomycin administration, lung tissue concentrations in the aerosol group were 63 (23, 119) µg/g and 0 (0, 19) µg/g in the intravenous group (P < 0.0001). A two-compartment weight-scaled allometric model with first-order absorption and elimination best fit serum pharmacokinetics after both routes of administration. Area under the time-concentration curve from 0 to 12 h was lower in the aerosol group in comparison to the intravenous group (56 [8, 70] mg · h · l vs. 121 [103, 149] mg · h · l, P = 0.002). Using a population model, vancomycin bioavailability was 13% (95% CI, 6 to 69; coefficient of variation = 85%) and absorption rate was slow (absorption half life = 0.3 h). CONCLUSIONS: Administration of vancomycin by nebulization resulted in higher lung tissue concentrations than the intravenous route.

Lung Ultrasound in Emergency and Critically Ill Patients: Number of Supervised Exams to Reach Basic Competence.

BACKGROUND: Lung ultrasound is increasingly used in critically ill patients as an alternative to bedside chest radiography, but the best training method remains uncertain. This study describes a training curriculum allowing trainees to acquire basic competence. METHODS: This multicenter, prospective, and educational study was conducted in 10 Intensive Care Units in Brazil, China, France and Uruguay. One hundred residents, respiratory therapists, and critical care physicians without expertise in transthoracic ultrasound (trainees) were trained by 18 experts. The main study objective was to determine the number of supervised exams required to get the basic competence, defined as the trainees' ability to adequately classify lung regions with normal aeration, interstitial-alveolar syndrome, and lung consolidation. An initial 2-h video lecture provided the rationale for image formation and described the ultrasound patterns commonly observed in critically ill and emergency patients. Each trainee performed 25 bedside ultrasound examinations supervised by an expert. The progression in competence was assessed every five supervised examinations. In a new patient, 12 pulmonary regions were independently classified by the trainee and the expert. RESULTS: Progression in competence was derived from the analysis of 7,330 lung regions in 2,562 critically ill and emergency patients. After 25 supervised examinations, 80% of lung regions were adequately classified by trainees. The ultrasound examination mean duration was 8 to 10 min in experts and decreased from 19 to 12 min in trainees (after 5 vs. 25 supervised examinations). The median training duration was 52 (42, 82) days. CONCLUSIONS: A training curriculum including 25 transthoracic ultrasound examinations supervised by an expert provides the basic skills for diagnosing normal lung aeration, interstitial-alveolar syndrome, and consolidation in emergency and critically ill patients.

Enhanced Recovery in Liver Transplantation: A Feasibility Study.

BACKGROUND: Enhanced Recovery After Surgery (ERAS) programmes after surgery are effective in reducing length of stay, functional recovery and complication rates in liver surgery (LS) with the indirect advantage of reducing hospitalisation costs. Preoperative comorbidities, challenging surgical procedures and complex post-operative management are the points that liver transplantation (LT) shares with LS. Nevertheless, there is little evidence regarding the feasibility and safety of ERAS programmes in LT. METHODS: We designed a pilot, small-scale, feasibility study to assess the impact on hospital stay, protocol compliance and safety of an ERAS programme tailored for LT. The ERAS arm was compared with a 1:2 match paired control arm with similar characteristics. All patients with MELD <25 were included. A dedicated LT-tailored protocol was derived from publications on ERAS liver surgery. RESULTS: Ten patients were included in the Fast-Trans arm. It was observed a 47% reduction of the total LOS, as compared to the control arm: 9.5 (9.0-10.5) days versus 18.0 (14.3-24.3) days, respectively, p <0.001. The protocol achieved 72.9% compliance. No differences were observed in terms of post-operative complications or readmission rates after discharge between the two arms. Overall, it was observed a reduction of length of stay in ICU and surgical ward in the Fast-Trans arm compared with the control arm. CONCLUSION: Considered the main points in common between LS and LT, this small-scale study suggests that the application of an ERAS programme tailored to the LT setting is feasible. Further testing will be appropriate to generalise these findings.

Influence of diluent volume of colistimethate sodium on aerosol characteristics and pharmacokinetics in ventilator-associated pneumonia caused by MDR bacteria.

Objectives: Nebulized colistimethate sodium (CMS) can be used to treat ventilator-associated pneumonia caused by MDR bacteria. The influence of the diluent volume of CMS on aerosol delivery has never been studied. The main objectives of the study were to compare aerosol particle characteristics and plasma and urine pharmacokinetics between two diluent volumes in patients treated with nebulized CMS. Methods: A crossover study was conducted in eight patients receiving nebulized CMS every 8 h. After inclusion, nebulization started with 4 million international units (MIU) of CMS diluted either in 6 mL (experimental dilution) or in 12 mL (recommended dilution) of normal saline in a random order. For each diluent volume, CMS aerosol particle sizes were measured and plasma and urine samples were collected every 2 h. Nebulization time and stability of colistin in normal saline were assessed. Results: The mass median aerodynamic diameters were 1.4 ±âŸ0.2 versus 0.9 ±âŸ0.2 µm (P < 0.001) for 6 and 12 mL diluent volumes, respectively. The plasma area under the concentration-time curve from 0 to 8 h (AUC0-8) of colistinA+B was 6.6 (4.3-17.0) versus 6.7 (3.6-14.0) µg·h/mL (P = 0.461) for each dilution. The total amount of colistin and CMS eliminated in the urine represented, respectively, 17% and 13% of the CMS initially placed in the nebulizer chamber for 6 and 12 mL diluent volumes (P = 0.4). Nebulization time was shorter [66 (58-75) versus 93 (69-136) min, P = 0.042] and colistin stability was better with the 6 mL diluent volume. Conclusions: Nebulization with a higher concentration of CMS in saline (4 MIU in 6 mL) decreases nebulization time and improves colistin stability without changing plasma and urine pharmacokinetics or aerosol particle characteristics for lung deposition.

Mesenchymal Stem Cell Microvesicles Attenuate Acute Lung Injury in Mice Partly Mediated by Ang-1 mRNA.

Microvesicles (MVs) derived from human mesenchymal stem cells (MSC MVs) were demonstrated to ameliorate inflammation in lungs. We have found their content of mRNA for keratinocyte growth factor was partly involved in their therapeutic effects. As MSC MVs also contained a substantial quantity of angiopoietin-1 (Ang-1) mRNA, which plays an essential role in vascular stabilization and resolving inflammation, we hypothesized that Ang-1 mRNA might similarly account for a part of their therapeutic effects. We downregulated Ang-1 mRNA expression in MVs, using a lentivirus vector carrying Ang-1 short hairpin RNA to transfect MSCs. A mouse model of lipopolysaccharide induced acute lung injury (ALI) was used in vivo. We also studied in vitro interactions between Ang-1 mRNA deficient MVs on macrophages and human lung microvascular endothelial cells. Compared with negative control, Ang-1 mRNA deficient MVs increased the influx of neutrophils and macrophage inflammatory protein-2 levels in bronchoalveolar lavage fluid by 136% and 105%, respectively, suggesting a deteriorative lung inflammation and a failure to restore pulmonary capillary permeability assessed by Evan's blue dye and bronchoalveolar lavage albumin level. In vitro, the addition of Ang-1 mRNA deficient MVs failed to maintain the integrity of endotoxin-stimulated microvascular endothelial cells and abrogated the decrease in tumor necrosis factor-α level and the increase in interleukin-10 level mediated by negative control in RAW 264.7 cells. In summary, the therapeutic effects of MVs in ALI, and their immunomodulatory properties on macrophages were partly mediated through their content of Ang-1 mRNA. Stem Cells 2017;35:1849-1859.

Modification of Tracheal Cuff Shape and Continuous Cuff Pressure Control to Prevent Microaspiration in an Ex Vivo Pig Tracheal Two-Lung Model.

OBJECTIVES: Microaspiration of subglottic secretions plays a pivotal role in ventilator-associated pneumonia. Impact of endotracheal tube cuff material and shape on tracheal sealing performance remains debated. The primary objective was to compare the tracheal sealing performance of polyvinyl chloride tapered, cylindrical and spherical cuffs. Secondary objectives were to determine the impact of continuous cuff pressure control on sealing performance and pressure variability. DESIGN: Prospective randomized ex vivo animal study. SETTING: French research laboratory. SUBJECTS: Seventy-two ex vivo pig tracheal two-lung blocks. INTERVENTIONS: Blocks were randomly intubated with cylindrical (n = 26), tapered (n = 24), or spherical (n = 22) polyvinyl chloride endotracheal tube cuffs. Two milliliter of methylene blue were instilled above the cuff to quantify microaspirations, and lungs were ventilated for 2 hours. Continuous cuff pressure control was implemented in 33 blocks. MEASUREMENTS AND MAIN RESULTS: Cuff pressures were continuously recorded, and after 2 hours, a microaspiration score was calculated. Tapered cuffs improved cuff sealing performance compared with spherical cuffs with or without continuous cuff pressure control. Compared with spherical cuffs, tapered cuffs reduced the microaspiration score without and with continuous pressure control by 65% and 72%, respectively. Continuous cuff pressure control did not impact sealing performance. Tapered cuffs generated higher cuff pressures and increased the time spent with overinflation compared with spherical cuffs (median [interquartile range], 77.9% [0-99.8] vs. 0% [0-0.5]; p = 0.03). Continuous cuff pressure control reduced the variability of tapered and spherical cuffs likewise the time spent with overinflation of tapered and cylindrical cuffs. CONCLUSIONS: Polyvinyl chloride tapered cuffs sealing enhanced performance at the cost of an increase in cuff pressure and in time spent with overinflation. Continuous cuff pressure control reduced the variability and normalized cuff pressures without impacting sealing performance.